The invention relates to a circuit for increasing, mainly near a reference level, a signal slope of a periodically occurring signal.
Such a circuit may, for example, be used in television. Herein it is customary to apply gamma correction to a television picture signal to match the linear opto-electronic recording characteristic to the non-linear electro-optical display characteristic. Besides this gamma correction, between a black level, fixed at a reference level, and a fixed peak-white value in the picture signal, it is advantageous to apply a further correction, that is to say a further increase of the signal slope specifically near the reference black level.